Pressure relief or bypass valves typically include an adjustable or non-adjustable spring-loaded plug which is seated on an internal orifice. The spring biases the plug into a sealed or closed position. When the pressure inside the system reaches a level sufficiently high enough to overcome the preset bias of the spring, also known as the differential pressure set point, the plug is lifted off of the orifice allowing pressurized fluid to flow past the valve and through the orifice. While this type of system is suitable for many applications, many presently available valves suffer from at least two deficiencies.
First, currently-available bypass valves tend to open and shut frequently producing a "chatter" or "water hammer" sound. This phenomena occurs when the valve is forced to cycle between the open and closed positions. Specifically, once the differential set point has been exceeded, the seal is broken and the valve opens thereby permitting flow through the valve. However, in most systems, and especially liquid systems, once a small amount of liquid is passed through the valve, the excess pressure is relieved in the system and the system pressure drops below the differential set point pressure. Consequently, the valve quickly closes. However, if the constriction or blockage that is causing the pressure increase has not been alleviated, pressure will quickly build up again to a level above the differential set point pressure and the valve will open again. Once a small amount of fluid is passed through the valve, pressure in the system is relieved and the valve closes again. Therefore, the valves are often being forced to cycle between an open and closed position which results in annoying chatter or water hammer sounds and also an undue amount of unnecessary vibration.
Second, many currently-available bypass valves may not be variable. That is, they may not permit incremental flow or small amounts of flow through the valve. Specifically, once the system pressure drops below the differential set point, currently-available valves will quickly close resulting in the chatter and water hammer sounds discussed above. These valves have only two positions--open and closed--and are unable to remain in a partially-open position for a period of time sufficient enough to permit an incremental, but substantial, amount of flow through the valve.
Accordingly, there is a need for an improved internal relief or bypass valve system for pumps and piping systems that provides full flowrate capacity relief when the differential pressure set point is exceeded and that does not chatter, vibrate or produce water hammer sounds. Further, there is a need for a relief or bypass valve that provides maximum flowrate relief as well as incremental flowrate relief. Finally, there is a need for an improved method of providing fluid bypass or pressure relief in pumps and piping systems that provides maximum capacity flowrate relief at pressures exceeding the differential pressure set point but eliminating any chatter, vibration or water hammer sounds.